Lower air dam



FIG. 1 is a front perspective view of a lower air dam showing our new design;

FIG. 2 is a top view thereof;

FIG. 3 is a bottom view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a rear view thereof; and,

FIG. 6 is a side view thereof.

It will be understood that the broken lines shown in the drawings illustrate portions of the lower air dam that form no part of the claimed design. 

CLAIM The ornamental design for a lower air dam, as shown and described. 